When riding a sled down a hill, it is often necessary to stop, sometimes rather quickly. One way to stop a sled is to lean backward, thereby increasing drag. However, this method is not particularly effective, particularly on ice or packed powder. Another method is to shift one's weight to quickly orient the sled so that it is perpendicular to the fall line. However, this method is difficult to execute.
In many cases, the only way to reliably stop the sled quickly is to jump off. At best, this is a somewhat ungraceful maneuver that is safe only at low speeds. Moreover, in a high-performance sled in which one is strapped into position, it is also impractical.